Read here about our first
impressions of the Type 1 DTM on the dyno when we first started developing
the VW Type 1 DTM.
Read
here one customer's testimonial on
why you need a DTM!
Read
here on what has been done to improve the DTM.
Click
here to view complete and unabridged testing results
for the DTM.
Technical Specifications
These
are the technical specifications and dimensions for The Aircooled Technology
DTM shroud kit
Offset
Shroud:
Shroud is set back on left
side to permit air to blow directly between #3 & #4 cylinders. This is the
main difference between the Aircooled Technology DTM cooling shroud and any
other cooling system currently available. Not even the Porsche 911 systems
have a means of directional airflow incorporated into their structure. The T1
DTM has vanes, as well as the offset design to rote the air more evenly to
each cylinder, evenly.
Air Distribution:
Shroud is internally
partitioned to distribute 40% to each cylinder bank and 20% to the oil cooler
housing. The VW Type 1 Aircooled Technology DTM scavenges air at a point such
that the air used to feed the oil cooler is not robbed from potential cooling
air that is meant for the cylinders, unlike other shrouds. At the same time,
the DTM provides 17% more cooling air to the oil cooler that houses a type 4
style oil cooler, which greatly increases overall cooling capacity, in most
cases eliminating the need for external coolers on smaller performance
engines, in street/strip applications.
Interior Control:
Right bank; direct to
cylinders, routed via one deflector toward the #2 cylinder. Left bank;
internal shroud form, multiple air guides and air deflectors designed to
reverse air flow to # 3 & #4 cylinders. The design of the shroud keeps all
airflow on the left side of the engine evenly distributed with minimal
stagnation.
Oil Cooling
Continuous oil cooling
during engine operation located in the same location as a doghouse shroud.
Engine speed determines quantity of cooling (same as a stock TIV engine).
System uses a stock VW Type 4 oil cooler which has 10% greater capacity than a
stock type 1 oil cooler. (new and rebuilt units are available) This system
helps to eliminate remote coolers which are subjected to insulating dirt, road
damage and blown oil transfer hoses. In most cases, an external oil cooler is
not needed on medium Performance engines. If needed, external oil cooler kits
complete with fans and thermostatic adapters are available.
Air Sealing Tin:
Unlike other conversions,
the Aircooled Technology DTM uses all your factory engine sealing tin for a
perfect fit in your engine bay, no cutting or modification required! Just bolt
on your existing TI sealing tins and the DTM fits like a glove!
Cooling Fan:
Unlike a 911 style
cooling system, which requires expensive fans, alternators, and pulleys, the
Aircooled Technology DTM uses your existing factory doghouse 1971 and later cooling fan. For
extreme applications, a Hybrid VW Type 4 Fan is being re-designed as a bolt-on
upgrade for even more cooling. The TI DTM will work with any cylinder head
including superflow and Competition Eliminators with minimal trimming and
modification that can be done by hand.
Specifications:
-
Shroud
Material......................Hand Laid Fiberglass
-
Finish.......................................Black Gel Coat
-
Air
Fans..................................1971-UP VW Type 1 (Doghouse style) or
Hybrid Type 4 cooling fan for increased capacity
-
Oil
Cooler…...…………….....Stock Type 4 oil cooler, 10% larger than a stock TI oil
cooler
-
Carburetion………………….Dual
Carburetors, Independent Runner EFI, or Custom. Single carburetors,
stock or aftermarket are not compatible due
to the offset shroud design.
-
Power
Supply.........................Stock VW Type 1, either Generator or
Alternator. The system utilizes the stock TI gen/alternator stand.
Unfortunately our initial testing results were not good enough for us to market the system,
and like many things we have developed, the Type 1 DTM had to go through some radical
changes to get to the point it's at today!
After our extensive testing of
Type I cooling systems in the winter of 2004, where we tested 14 different
stock and aftermarket cooling systems, we had basically given up all hope on
the Type I DTM. The system had given us very disappointing results in its
ability to control head temperatures on all 4 cylinders of the engine. when an
off the shelf, aftermarket chrome 36HP style shroud beat the Type I DTM in
direct testing I gave up on any hopes of making it a marketable system. We did
continue and finished our cooling system comparisons and attained valuable
data that NO ONE else has concerning the hidden truths about cooling systems
that are on the market today.
It seemed that no matter
what we did to the internals of the system, nothing helped it to cool better.
We tried more cooling vanes, less cooling vanes, differently placed
deflectors, different drive ratios and fans. We even tried drilling holes in
pertinent areas of the shroud in hopes to make it actually work as well as the
Type IV DTM!
As a member of many online
forums, I shared my testing results and disappointments with the Type I DTM
with the world. Almost immediately following the announcement that the Type I
DTM was to become a part of history my inbox filled with emails and the forums
were buzzing with individuals urging me to somehow make the system work. Not
being an engineer, or cooling system expert I was not sure I could make it a
reality. the testing had taught Brent and I that without a few key ingredients
any cooling system would not function correctly, and one of those ingredients
was air pressure- then I had an idea!
The Type I DTM did have a very
strong edge over the other systems, and that was it incorporated a Type 4 oil
cooler and shoved alot of airflow into it in Joe's design. Knowing that I
decided to take a break from the system for a few weeks and come back to the
DTM after I finished a large project for a customer that had a timeline. I did
research and talked to many people outside the VW industry about cooling
systems and basic airflow. Each of them had a different idea, but almost all
them told me that the system could be made to work if the pressures inside the
shrouds upper plenums could be raised high enough to overcome the static that
creates turbulance.
Then one night I called Mr. Bob
Hoover, a VW veteran that was good friends with Joe Locicero, the
inventor of my DTM systems. Mr. Hoover is a wealth of knowledge and said that
he knew the problem and that he and Joe had discussed it in the past. He went
on the explain to me that the stock cooling system used an "Eipper 320 series"
AIRFOIL in its design!! Then it hit me, and I felt really dumb that being from
an aircraft background I had never experimented with a vane shaped like an
airfoil to speed up the air as it made its way through the shroud. It was very
odd that I had talked to several engineers that were experts, but Mr. Hoover
brought up something that they never did. When I asked one of them about it he
said "its not the key, there are more important issues to overcome".
As time and testing would tell,
the airfoil was the key and Mr. Hoover was right! It was no wonder that adding
regular old "vanes" to the shroud produced worse results in the early testing-
they simply CAUSED problems and created more resistance, and kept more air
from going to the left bank cylinders. By adding airfoils the air is literally
sucked over the leading edge of the airfoil, and sped up over the trailing
edge of the airfoil, while helping to build plemum pressure. This pressure
allows the air to be more easily directed by deflectors and less detailed
types of vanes to the hottest parts of the heads! That area, by far is the
exhaust ports!
Now that we've added the needed
airfoils,
what's the testing have to say about the Type 1 DTM?
Want to read more, continue on to page two.
IF YOU WANT TO READ THE UNABRIDGED TESTING RESULTS,
THEY WILL ALSO BE ACCESSIBLE THROUGH PAGE TWO, OR BY CONTINUING BELOW.
What you are about to view
are all of our spreadsheets filled with raw data from testing the Type I DTM.
These spreadsheets were used to test changes that were made to the cooling
system and their effects with sustained loads. The very first graph (test
#1) is the very first test run that we every did with the Type I DTM..
Compare it with tests #15, 16 and 17 (our most recent tests) and you will
see vast differences in cooling and even temperatures. This is what seven
months of research and trial and error were able to do for this cooling
system.
It is very rare that any
company would share test results with the public, but I chose to do so
because it is a great illustration of actual development. These days so many
companies just build something and throw it onto the market with a huge
advertisement and let it be. The cooling of our engines is the most important
key to power, reliability and longevity. I am proud, to have worked these long
hours to develop Joe’s system into a reality and show you just what we tried
to make it work. Pay close attention to the details in the ”cooling system
specs box” in each spreadsheet as it will give you an idea of what changes we
made to the system and what the end results were. Keep in mind that we had
over 100 test runs (many partial runs) on the test engine in January and only
14 of them are logged here. The reason for that is that many of the changes
didn’t work and we noticed it in just a few minutes and the test was aborted
to save fuel and time and to allow the engine cool for the next change. The
runs you see here were our best and most comparative, the others were trashed
while we went back to the drawing table and beat our heads on the wall.
Please note that this type
of test work is very demanding on all those involved and that we all gave up
our lives for 17 days to attain these figures as well as the figures from 13
other systems, both stock and aftermarket, including the “famed” Porsche 911
systems ( which didn’t work worth a DAMN in our testing). To gather this test
data I expended over 400 dollars in fuel, built a specific engine for the
basis (4,000.00+) and ended up destroying my dyno after a driveshaft failure
from the constant harmonics of the test (6,000.00). This is not to mention the
man hours Brent and I and even my friends gave up to get the data. As you can
see we did our best to make our product the best we could and in the first
round of testing, all of it was a loss for the DTM, but we did gain tremendous
amounts of knowledge about cooling in general as well as other systems that we
had never been associated with. We have done our part!
This testing did not stop on
the dyno. We employed 11 systems to be tested in the field on individual’s
engines of various sizes and tune, as well as my personal test car, The
Bluebonic Plague. These test shrouds are being worked every day, and on the
weekends in some race vehicles to give us great feedback about running
temperatures to back up our claims with testimonials from neutral parties that
have nothing to gain from the DTM, except even running temps on their engine!!
as of this writing we are sending out updated airfoils for our field testers
to use in their shrouds and see if they see the same changes that we did, and
the test engine is now being installed into my car yet again for some road
test miles and a few passes down the strip!
Now we ask a favor of you.
As you view our results, view them with respect, please do not send us emails
with ideas, or emails with suggestions, or bring new ideas to our attention.
We let the engine and cooling system show us its issues and we have worked to
solve them and spent eight months of our lives doing so. We constantly get
emails from those who have wonderful ideas, and great intentions and most of
the time we do listen and we do learn, however that is not true in this
instance. I am not stuck on being perfect, and I’m not an expert but I have
seen that NO ONE really understands these cooling systems, and engines…The
more I tested and learned the more apparent this became. I quit “listening” to
the so called “Experts” and started “doing” what we thought was right. I made
many mistakes and learned from them, just like with my engine design and
assembly. All in all the end result was a fully tested system that works and
it was made possible by a lot of trial and error, a few brain cells and
dedication.
Note, The data you see here
is plain and simple. It does not show you the fact that each different
cylinder, and cylinder head used for TI engines has made impacts on the DTM’s
ability to cool, or for that matter any other systems ability to cool in our
testing. Its main goal is to show you that as a general rule that our system
works, and works AWESOME! When different cooling fins are used on cylinders
and heads the upper plenums of the shroud have their pressures increased or
decreased, this effects the running temperatures and does so severely with
some arrangements. All our testing pictured here was done with cylinder heads
with exacting fins and surface area as stock, (for good measure and for
standardization) and test runs 15,16,17 were done with different cylinder
arrangements- you can note how the cylinders impacted the job the DTM was able
to do…. Basically what I’m saying is that no matter how hard we try, the vast
numbers of variations in the Type I engine will cause some fluctuations in the
results that each Type I DTM purchaser may see. I will be making a page with
many pictures to illustrate the variations that I’m referring to very soon.
Click
here to read more about our
extensive Type 1 DTM cooling system tests.
(366 second download time @ 3.6kb/sec)
Jake Raby
Copyright 1997-2004 Raby’s Aircooled Technology.
